• Title/Summary/Keyword: Yi Ko

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Characteristics of Voltage-Dependent Clacium Uptake and Norepinephrine Release in Hypothalamus of SHR

  • Yi, Sook-Young;Kim, Yun-Tai;Kim, Kyeong-Man;Ko, Kwang-Ho
    • Archives of Pharmacal Research
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    • v.17 no.4
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    • pp.226-230
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    • 1994
  • The characteristics of voltage-dependent ^{45}Calcium$ uptake and norepinephrine release as factors controlling neural activities in the hypothalamus which is an important regulatory site for cardiovascular function wre studied. Two groups of animals : male spontaneously hyperterisive rat (SHR) and age-matched nomotensive wistar rat (NW) were used in this study. Animals at 4, 6 and 16 weeks of age were sacrificed by decapitiation and the hypothalamus was dissected out. Voltage-dependent calcium uptake and norepinephrine release were determined from hypothalamic synaptosomes either in low potassium (5 mM) or high potassium (41 mM) stimulatory conditions by using ^{45}Ca$ isotope and HPLC-ECD techniques. Degrees of voltage-dependent ^{45}Calcium$ uptake and norepinephrine release evoked by calcium uptake in the hypothalamus of prehypertensive phase (4 weeks old) of SHR were significantly smaller than those in NW of the same age. However, in the developmental phase (6 weeks old) and the established phase (16 weeks old) of hyperrtension in SHR, degrees of voltage-dependent ^{45}Calcium$ uptake and norepinephrine release were similar to those of age-matched normotensive wistae eats. These data imply that the deficit in hypothalamic norepinephrine release might be an important underlying factor for the development of hypertension in SHR.

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Web-based Fluid Dynamics Education using e-AIRS System (e-AIRS 환경을 활용한 웹기반의 유체역학 교육)

  • Kim, J.H.;Yi, J.S.;Ko, S.H.;Kim, C.;Kim, Y.H.;Moon, J.B.;Cho, K.W.
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03b
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    • pp.212-215
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    • 2008
  • e-AIRS, an abbreviation of 'e-Science Aerospace Integrated Research System,' is a virtual organization supporting CFD(computational fluid dynamics) simulations, remote experimental service, and collaborative and integrative study between computation and experiment. e-AIRS works on the e-Science environment and research process is accomplished through the web portal. By the system development since 2005, a stable education system with the full support on fluid dynamics is successfully established and utilized to various fluid dynamic lectures in universities. By using e-AIRS system during a lecture, students can conduct the full CFD simulation process on the web and inspect the wind tunnel experiment via Access Grid. This kind of interactive lecture makes students to have a deeper understanding on the physics of fluid, as well as the characteristics of numerical techniques. The current paper will describe system components of e-AIRS and its utilization on education.

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Knowledge of Stroke Symptoms and Risk Factors among Older Adults (노인의 뇌졸중 증상과 위험요인에 대한 지식정도)

  • Han, Nam-Yi;Ko, Eun-Ah;Hwang, Seon-Young
    • Korean Journal of Adult Nursing
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    • v.21 no.3
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    • pp.314-323
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    • 2009
  • Purpose: This descriptive study was conducted to identify the level of knowledge of stroke symptoms and risk factors among older adults. Methods: A total of 200 older adults over 65 years of age were conveniently recruited from out patient departments of two hospitals and a health care center from October to November 2008. The level of knowledge was assessed using both open-ended questions and a structured questionnaire based on semi-structured interviews. Data were analyzed by t-tests and ANOVA using the SPSS program. Results: 52.5% of the sample had hypertension and 30% had diabetes. The mean knowledge scores for symptoms and risk factors were $8.4{\pm}3.1$ (out of 15) and $9.5{\pm}3.9$ (out of 16), respectively. The older adults who had lower education, lower family income, and who lived in rural areas were more likely to have less knowledge of stroke symptom and risk factors (p < .05). There was no significant knowledge difference between the older adults who had at least one risk factor and those who had no risk factor for stroke. Conclusions: Educational intervention should be focused on informing older adults who are at risk for stroke about the early symptoms and management of risk factors, especially those who have low education and low social status.

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Spontaneous Thoracic Spinal Cord Herniation - Case Report - (자발성 흉추부 척수 탈출증 - 증례보고 -)

  • Kim, Young Jin;Kim, Young Soo;Kim, Ju Hun;Yi, Hyeong Joong;Ko, Yong;Oh, Sung Hun;Kim, Kwang Myung;Oh, Suck Jun
    • Journal of Korean Neurosurgical Society
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    • v.30 no.10
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    • pp.1237-1240
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    • 2001
  • Spontaneous herniation of the spinal cord is a very rare. It's clinical symptom presents with progressive myelopathy. A 42-year old male patient who presented the progressive left leg weakness and Brown-Seqaurd syndrome is presented. MRI showed a typical finding of dural defect and herniation of the cord on the level of T3-4. Repair of dural defect using an artificial dura and reposition of cord herniation were undertaken after three level laminectomies with SSEP monitoring. Postoperatively, symptoms were improved rapidly. In our knowledgement, this is first case being reported in Korea. This entity, although rare, should be considered in the differential diagnosis of myelopathy in the absence of a mass lesion.

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Rapidly Evolving Craniopharyngioma after Resection of Supratentorial Meningioma - Case Report - (천막상부 뇌수막종 절제후 단기간에 발생한 두개인두종 - 증례보고 -)

  • Kim, Sung Su;Ko, Yong;Yi, Hyeong Joong;Kim, Young Soo;Oh, Seong Hoon;Kim, Kwang Myung;Oh, Suck Jun
    • Journal of Korean Neurosurgical Society
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    • v.30 no.10
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    • pp.1220-1223
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    • 2001
  • Authors experienced a unique case of craniopharyngioma which had evolved rapidly after 4 years of total resection for supratentorial meningioma. A 58-year-old woman presented with headache and visual deterioration. Previously, she had undertaken surgical removal of frontal convexity meningioma 4 years ago and had been well without any postoperative sequelae thereafter. Brain magnetic resonance imaging demonstrated a newly developed suprasellar mass. Pertinent operative procedure was performed and histological verification was made as an adamantinomatous craniopharyngioma. She has been showing unremarkable clinical course up to date. Possible pathogenic mechanisms of de novo development of craniopharyngioma are disscussed with review of case.

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Macromolecular Crowding Enhances Interaction of ${\alpha}$-synuclein with Vesicles

  • Kim, Yoon Suk;Kim, Jeonghan;Yi, Chi A;Ko, Jesang;Park, Yong Serk;Lee, Seung-Jae
    • Biomedical Science Letters
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    • v.18 no.4
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    • pp.329-337
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    • 2012
  • ${\alpha}$-synuclein (${\alpha}$-syn) is known to be implicated in the pathogenesis of Parkinson's disease and transiently bind to biological vesicles. In this study, we examined the effect of molecular crowding on the interaction of ${\alpha}$-syn with biological vesicles by using inert polymers since the environment of proteins in cells are crowded with other macromolecules. The addition of different polymers including polyethylene glycol, dextran, and ficoll enhanced the binding of ${\alpha}$-syn to vesicles in a concentration-dependent manner and the association of ${\alpha}$-syn with vesicle was proportionally augmented by increased expression of ${\alpha}$-syn. However, molecular crowding had a neglectable effect on the vesicle binding of ${\alpha}$-syn mutants (A30P, TG6), which has been reported to show impaired vesicle binding capacity. These results suggest that transient interaction of ${\alpha}$-syn with vesicles occurs more commonly in cells than expected implying interaction with vesicles may be one of the physiological processes in which ${\alpha}$-syn is involved.

N$_2$ Plasma Treatment Effects of Silicon Nitride Insulator Layer for Thin Film Transistor Applications

  • Ko, Jae-Kyung;Park, Yong-Seob;Park, Joong-Hyun;Kim, Do-Young;Yi, Jun-Sin;Chakrabarty, K.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.563-566
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    • 2002
  • We investigated to decrease the leakage current of SiNx film by employing $N_2$ plasma treatment. The insulator layers were prepared by two step process; the $N_2$ plasma treatment and then PECVD SiNx deposition with $SiH_4$, $N_2$ gases. To prove the influence of the $N_2$ plasma treatment, the Si substrate was exposed to the plasma, which was generated in Ne gas ambient. Without plasma treatment SiNx film grow at the rate of 7. 03 nm/min, has a refractive index n = 1.77 and hydrogen content of $2.16{\times}10^{22}cm^{-3}$ for $N_2/SiH_4$ gas flow ratio of 20. The obtained films were analyzed in terms of deposition rates, refractive index, hydrogen concentration, and electrical properties. By employing $N_2$ plasma treatment, interface traps such as mobile charges and injected charges were removed, hysteresis of capacitance-voltage (C-V) disappeared. We observed plasma treated sample were decreased the leakage current density reduces by 2 orders with respect to the sample having no plasma treatment.

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De-Noising and Contour Preserving Digit Enhancement for Meter Digit Recognition (계량기 숫자 인식을 위한 잡영 제거 및 윤곽보존 숫자강화)

  • Yi, Eun-Gyoo;Ko, Jae-Pil
    • Proceedings of the Korean Information Science Society Conference
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    • 2006.10b
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    • pp.515-520
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    • 2006
  • 계량기 숫자 인식은 일반적으로 사용되고 있는 아날로그 계량기에 카메라를 부착하여, 검침 시 숫자 계기판 영상을 전송받고, 그 영상으로부터 숫자를 추출 및 인식하는 기술이다. 계량기 숫자 인식에서는 카메라의 설치 상태 및 기타 환경적인 요인들로 인해 숫자 계기판 영상의 일관성 있는 취득이 어렵게 된다. 본 논문에서는 숫자 인식에 악영향을 미치는, 취득 영상의 상태 변화를 보정해주기 위해 잡영 제거 및 윤곽보존 숫자강화를 제안하였다. 잡영 제거를 위해 잡영을 분포 위치에 따라서 세 가지 타입으로 나누었으며, 각 타입별로 잡영 제거를 하였다. 윤곽보존 숫자강화 과정에서는 일반적인 이진화 기법이 가지는 테두리 정보손실을 최소화할 수 있도록, 숫자 테두리의 명도를 보존하면서 숫자 중심부분의 밝기를 강화시켰다. 전처리 전/후의 인식률 비교 실험을 위해 SVM(Support Vector Machines)을 사용하였으며, 학습 데이터 1,409장과 조명 상태를 달리하여 취득한 1,782의 테스트 데이터를 실험 데이터로 사용하였다. 실험 결과, 81.09%라는 성능 향상을 확인하였으며 이는 제안한 전처리 기법이 조명으로 인한 데이터의 상태 변화 문제를 해결해줌으로써 인식 성능 향상에 크게 기여한다는 것을 입증해준다.

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Composite Beam Element for Nonlinear Seismic Analysis of Steel Frames (강재 골조의 비선형 지진해석을 위한 합성 보 요소)

  • Kim, Kee Dong;Ko, Man Gi;Yi, Gyu Sei;Hwang, Byoung Kuk
    • Journal of Korean Society of Steel Construction
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    • v.14 no.5 s.60
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    • pp.577-591
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    • 2002
  • This study presented a composite beam element for modeling the inelastic behavior of the steel beam, which has composite slabs in steel moment frames that are subjected to earthquake ground motions. The effects of composite slabs on the seismic behavior of steel moment frames were investigated. The element can be considered as a single-component series hinge type model whose predicted analytical results were consistent with the experimental results. Likewise, the element showed a significantly better performance than the bare steel beam elements. The composite model can also predict more accurately the local deformation demands and overall response of structural systems under earthquake loading compared with the bare steel models. Therefore, composite stabs can significantly affect locally and globally predicted responses of steel moment frames.

A Brain-based Study with Two Groups of High Math Anxiety and Low Math Anxiety through the Non-psychological Remedy Program of Functional Tasks (비심리적 처치프로그램에 의한 고등학생 수학불안집단 간의 뇌파 연구)

  • Choi-Koh, Sang Sook;Lee, Chang Yeon
    • The Mathematical Education
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    • v.55 no.3
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    • pp.383-396
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    • 2016
  • This study investigated highschool students' brain waves on functional tasks such as a transition(F task) from equation to graph and the other transition(G task) vice versa. A total of 39 students participated in the study who attended a high school located in Gyunggi province. These students were divided into two groups, HMA and LMA by MASS test revised by Ko, & Yi (2012). The functional tasks for the stroop task to measure EEG were provided from a previous study, Seok(2015). The results indicated two groups on G tasks showed deeper and wider brain waves which demonstrated G tasks were more difficult than F tasks. However, HMA group had an effect of the non-psychological program which had given more chances on G tasks rather than F tasks within Students' Zone of Proximal Development. Also, HMA group's brain waves had more ranges in amplitude and width of waves. These results imply that the characteristics of students' brain waves with math anxiety are consistent to the previous studies.